Abstract
In order to evaluate the quantity and quality of forage when intercropping forage sorghum (Sorghum bicolor L.) with lathyrus (Lathyrus sativus) and hairy vetch (Vicia villosa), and using different weed management methods such as double cropping, a factorial experiment in a randomized complete block design with three replications was carried out at the research station of the University of Zanjan over two growing seasons (2015 and 2016). In this experiment, the intercropping of forage sorghum with lathyrus and hairy vetch at six levels with single cropping of forage sorghum, lathyrus, and hairy vetch, and three weed management strategies (no weed control, full weed control, and single weed control) was evaluated. The results showed that most forage sorghum traits were significantly (p ≤ 0.05) affected by different sowing ratios. The highest fresh forage yield of sorghum (77.9 ton/ha) and lowest (49.0 ton/ha) were obtained with sorghum + 33% hairy vetch and sorghum + 100% lathyrus, respectively. Forage qualitative traits were also affected by intercropping and weed management. The highest average acid detergent fiber (ADF), neutral detergent fiber (NDF), and total ash percentage (ASH) were obtained with 100% sorghum + 66% lathyrus and 33% hairy vetch. The results showed that sorghum intercropping with 33% lathyrus led to a significant reduction in dry matter intake and relative feed value with no weed control and single weed control. This study demonstrated that, by selecting the appropriate intercropping ratios and forage legumes, we could largely control sorghum weeds in addition to improving the quantitative and qualitative yield of sorghum forage.
Highlights
Shortage of forage is one of the main problems for livestock in Iran [1]
The results showed that in two years of study only sorghum cultivation with 66% hairy vetch could significantly increase the percentage of water-soluble carbohydrates in comparison to sole sorghum
The results showed that sorghum cultivation with 66% and 100% hairy vetch, as well as sorghum cultivation with 100% lathyrus, led to a significant increase in Relative Feed Value (RFV) under full weed control conditions compared to sole sorghum cultivation
Summary
Forage crops are among the most important crops in livestock feeds and, for supplying livestock products for human consumption. Due to its unique morphological and physiological characteristics, sorghum has been introduced as a drought resistant crop and, as such, has fewer water requirements than other crops. It can be used in arid and semi-arid regions as a reliable source of forage [2]. Sorghum is a major C4 plant that has high growth potential and high production [3,4,5,6,7,8]. Weed management is one of the most important aspects of sorghum farming. The loss of yield varies from 10% to 100%, depending on the competitive ability of the weeds and crops, Horticulturae 2020, 6, 78; doi:10.3390/horticulturae6040078 www.mdpi.com/journal/horticulturae
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